For words that have only 3 letters, there isn't a 4th letter. One example is with the word “include”, there are no a lot more letters afterwards and therefore has to be the word "incorporate". The word “addict” is in the BIP39 wordlist but you would have made use of https://franciscougju442.bravesites.com/entries/general/Opening-the-Power-of-BIP39-An-Extensive-Consider-Word-Lists-and-Secure-Budgets